bluuebunny/crossref_metadata_2025_split huggingface dataset:
Gene expression and protein distribution of inter‐α‐trypsin inhibitor in three human hepatoma cell lines.
Authors: Héron Antoine , Borghi Hélène , Callé Aleth , Bourguignon Jeannette , Diarra‐Mehrpour Maryam , Martin Jean‐Pierre , Sesboüé Richard 
Published: October 2002

AbstractIn standard culture conditions, three human hepatoma cell lines, Hep3B, PLC/PRF/5 and HepG2, were characterised by a predominant transcription of only two (H2 and L) among the four genes involved in the synthesis of inter‐α‐trypsin inhibitor (ITI)‐related proteins. Pulse‐chase experiments followed by immunoprecipitation with specific anti‐L and anti‐H ITI antisera showed that the proteins synthesised displayed a restricted L and/or H2 antigenic reactivity. Furthermore, while Hep3B and PLC/PRF/5 lines only synthesised ITI precursors (mainly the L‐form), HepG2 cells were able to secrete an ITI‐like protein. Immunocytochemical analyses substantiated these results with uneven distribution of heavy and light‐chain polypeptide reactivity among the cells. The use of hepatoma cell models for the study of protein synthesis and assembly must therefore be considered cautiously.
Involvement of tubulin in MPP+ neurotoxicity on NGF‐differentiated PC12 cells.
Authors: Cappelletti Graziella , Incani Cristina , Maci Rosalba 
Published: October 2002

AbstractIn vivo, the neurotoxin MPTP is oxidated to MPP+, which is toxic to dopaminergic neurons. In this paper, we have used MPP+ as a tool to evoke neurotoxicity in the PC12 cell line and investigate the intracellular events that are involved. A cytotoxicity test, performed on undifferentiated and NGF‐differentiated PC12 cells, showed that MPP+ is much more toxic on differentiated cells and indicated the suitable range of concentrations for studying the starting events evoked by the neurotoxin. By indirect immunofluorescence we have shown that the localisation of α ‐ and β ‐tubulin in NGF‐differentiated cells was modified by a 24 h treatment with 15 μmol/l MPP+. A biochemical analysis was performed on cell extracts and the results showed that MPP+ treatment induced an increase in α ‐tubulin levels and a decrease in β ‐tubulin levels. These results suggest the involvement of the two microtubule proteins in MPP+ neurotoxicity on NGF‐differentiated PC12 cells.
Transfection of normal human skin fibroblasts with human α1(I) and α2(I) collagen gene constructs and evidence for their coordinate expression
Authors: Hata Ryu‐Ichiro 
Published: October 2002

AbstractType I collagen is composed of two α1(I) chains and one α2(I) chain that together form a unique triple helical structure. The genes for these chains are located on different chromosomes but their expression is tightly regulated. In order to investigate the mechanism of regulation of coordinate expression of these genes, I examined conditions for the efficient transfection of normal human skin fibroblasts with luciferase reporter gene constructs containing noncoding region of the first exon and the upper 500 base pairs sequence of the α1(I) or α2(I) gene. Expression ratio of these two reporter gene constructs was two to one, indicating these regions of α1(I) and α2(I) genes contain essential regulatory elements for the coordinate expression of α1(I) and α2(I) genes located on different chromosomes.
THE DENDRITIC CELL: ITS POTENT ROLE IN THE RESPIRATORY IMMUNE RESPONSE
Authors: LAMBRECHT B. N. , PAUWELS R. A. , BULLOCK G. R. 
Published: October 2002

AbstractThe importance of the dendritic cell for the capture of antigens and initiating an immune response is now well recognized. Whereas much is known about their structure and function, their lineage is still not clear. Studiesin vitrohave demonstrated that the regulated maturation of function that occurs in culture explains many of thein vivoevents relating to antigen capture and presentation. The control over maturation and migration of these cells to the immune system is decisive as to whether an immune response is mounted or not. ‘Danger ’ signals provided by conserved bacterial products or by microenvironmental cytokines are important regulators. Dendritic cells have been clearly involved in the development of respiratory disease and our understanding of their involvement will have an impact on our future therapeutic strategies.
EARLY EFFECT OF MOSQUITO LARVAE EXTRACT ON MOUSE CELLS PROLIFERATIONIN VIVO
Authors: RONDEROS JORGE R. 
Published: October 2002

AbstractIt has been demonstrated that mosquito larvae crude extract has an inhibiting effect on the mitotic rate of several mouse cell populations. The sampling period was 16–24h after treatment, when mitotic peak normally occurs. The present paper reports the effect of mosquito larvae crude extract on the proliferation of hepatocytes, renocytes, Lieberkhün crypt enterocytes, and sialocytes. In this case, the sampling period covered the dark phase of the day, during the first 12h after treatment. Colchicine‐arrested metaphases were controlled at 20/04, 00/08 and 04/12 (Time of Day/Time Post Injection). The mitotic rate was significantly increased in hepatocytes and renocytes and inhibited in duodenum enterocytes. In view of the time chosen to administer the treatments and the time elapsed until sampling, we conclude a probable effect of the extract at the G2‐M point of the cell cycle.
IMPLICATION OF INVOLVEMENT OF RAT CHROMOSOME #2 IN SPONTANEOUS TRANSFORMATION OF THE RAT‐2 CELL LINE
Authors: KRISHNAVENI L. , GHOSH S. N. 
Published: October 2002

AbstractUsing anin vitromodel for cell transformation, the relationship between specific chromosomal aberration and phenotypic changes was studied at different passages of Rat‐2 cell line. A marker chromosome resulting from a translocation [t(2;7)] was found to be associated with focus formation in soft agar. Conversely, the loss of this marker chromosome was found to be associated with phenotypic reversion. These results suggest an association of this marker chromosome with phenotypic transformation for the Rat‐cell line.
CONSTITUTIVELY MIGRATING MALIGNANT RAT LIVER EPITHELIAL CELLS PRODUCE A MIGRATION‐STIMULATING ACTIVITY FOR EPITHELIAL CELLS (eMSA)
Authors: ECKSTEIN BARBARA K. , BADE ERNESTO G. 
Published: October 2002

AbstractConstitutively migrating malignant rat liver epithelial cells obtained by Ha ras transformation exhibit a fibroblastoid phenotypein vitro. The cells deposit the anti‐adhesive extracellular matrix (ECM) protein tenascin into their ECM migration tracks. The serum‐free medium conditioned by these constitutively migrating cells contains an epithelial migration‐stimulating activity (eMSA) that is neither cell‐type‐, nor species‐specific. This eMSA fractionates in the range of 30 to 50kDa and binds to Mono‐Q, Mono‐S, and with low affinity to heparin—Sepharose. The conditioned medium also induces the expression of the serine proteinase inhibitor PAI‐1. Both migration and expression of PAI‐1 are inhibited by cyclic AMP, as previously shown for the migration of the non‐transformed liver epithelial cells induced by several growth factors that act through tyrosine kinase receptors. These results suggest that the eMSA might act through signal transduction pathways similar to those of the growth factors previously studied. It is postulated that the eMSA, through both autocrine and paracrine mechanisms, is at least partially responsible for the malignant phenotype of the transformants.
ALTERATIONS IN IMMUNOGLOBULIN SYNTHESIS DURING ADRIAMYCIN‐INDUCED APOPTOSIS IN MOUSE HYBRIDOMA CELLS
Authors: MELIKSETIAN M. B. , DAVTYAN T. K. , CHIRKOWA I. V. , ALEXANYAN YU.T. , IGNATOVA T. N. 
Published: October 2002

AbstractChanges in the immunoglobulin synthesis in mouse hybridoma 1F7cell line following exposure to the anticancer drug adriamycin were studied. It was shown that adriamycin in concentrations up to 0.1μg/ml causes dose‐dependent reversible enhancement of immunoglobulin heavy γ2bchain synthesis, and to a lesser extent, κ light chain synthesis. Enhancement of γ2bheavy chain synthesis accompanies an increase in Ig γ2bmRNA levels. Enhancement of DNA‐binding activity of another B‐cell specific protein, octamer transcription factor Oct‐2 was also observed. Cell cycle analysis revealed accumulation of the ADR‐treated cells in G2/M phase of cell cycle. These changes in hybridoma cells preceded the onset of internucleosomal DNA fragmentation and appearance of morphological characteristics of apoptosis. These findings suggest, that differentiation‐related processes occur during the latent phase of apoptosis induced by adria‐mycin in mouse hybridoma cells.
PROTOANEMONIN‐INDUCED CYTOTOXIC EFFECTS INEUGLENA GRACILIS
Authors: MARES D. , BONORA A. , SACCHETTI G. , RUBINI M. , ROMAGNOLI C. 
Published: October 2002

AbstractThe changes that protoanemonin, an antimicrobial agent of natural origin, brought about in the algaEuglena graciliswere studied with light and electron microscopy and with flow cytometry. The compound proved lethal for the alga at a dose of 5×10−5m. At the sublethal dose of 3.5×10−5m it caused: marked inhibition of growth; increase in the average cell volume; inhibition of cytokinesis and induction of coenocytic organisms; loss of the primary_articlegellum and stigma. Most nuclei were arrested in the G2/M phase of the cellular cycle. The chloroplasts were still well organized, but there was a conspicuous decrease in carotenoids and chlorophyllsaandbwith a corresponding increase in pheophytins. The multifarious alterations seen in Euglena are discussed on the basis of a possible interaction between this lactone and several enzymatic systems.
INHIBITION OF LACTOGENIC ACTIVITIES OF BOVINE MAMMARY GLAND EXPLANTS BY THE WHEY FRACTION OF BOVINE MILK
Authors: SHAMAY A. , SHINDER D.A , BRUCKENTAL I. , SILANIKOVE N. 
Published: October 2002

AbstractThe regulation of milk constituents, synthesis and secretion in tissue cultures of the bovine mammary gland was altered by a whey fraction of bovine milk. α‐Casein gene expression, casein secretion and fatty acid synthesis were inhibited by the whey fraction in a dose‐dependent manner. The whey fraction inhibited the enhancement activity of prolactin on α‐casein gene expression and fatty acid synthesis, and also inhibited casein secretion to the medium, in explants cultured in a medium with or without prolactin. No effect on the expression of the β‐lactoglobulin gene was found.
UVC‐INDUCED CELL DEATH OF IL‐2‐DEPENDENT HUMAN LYMPHOCYTES
Authors: Radziszewska E. , Piwocka K. , Skierski J. , Sikora E. 
Published: October 2002

AbstractWe compared the in vitro propensity of human IL‐2‐dependent lymphocytes (young proliferating and senescent non‐proliferating), and resting peripheral blood lymphocytes (PBLs) to undergo UVC‐induced apoptosis. The activities of AP‐1 (activator protein‐1), CRE (cAMP response element) and OCT‐1 (octamer‐1) transcription factors in all lymphocytes were also assessed. At 24h after UVC treatment, half of young proliferating T lymphocytes and about a quarter of PBLs and senescent non‐proliferating cells were apoptotic, as shown by flow cytometry. However, only in young lymphocytes were both typical DNA ‘ladder’ and Bcl‐2 downregulation evident. The AP‐1 transcription factor was activated by UVC in IL‐2‐dependent young and senescent, but not resting lymphocytes. Taken together, the data show different propensities of resting, proliferating and senescent human lymphocytes to undergo UVC‐induced apoptosis and AP‐1 activation.
Causes of Two Patterns of Lichen Zonation on Cobbles in the Negev Desert, Israel
Authors: Kidron Giora J. 
Published: October 2002

AbstractTwo patterns of lichen zonation on cobbles were observed in the Negev Desert, Israel: growth on the top of the cobble and growth on the cobble margins. The causes of the different patterns are examined. Microscopic examinations did not reveal any textural or structural differences between the top and the margins of each cobble, excluding the possibility that mineralogical differences are responsible for the patterns observed. Field measurements have, however, shown a significant difference in the quantities of average daily dew, with the top of the cobbles receiving approximately double the quantity received at the margins. These results were consistent on all cobbles examined, loose as well as partially embedded cobbles. In addition, field observations following rain noted a greater moistness at the margins of partially embedded cobbles. This phenomenon, also observed following sprinkling experiments, was explained by water capillary rise. Whilst the top dwelling pattern may be explained by the significantly larger quantities of dew on the top of the cobble, the margin-dwelling pattern may be explained by greater moistness at the cobble-soil interface due to water capillary rise. Providing that the threshold moisture duration is met, lichen colonization may be expected. An estimated annual daylight moisture duration of approximately 260-320 h is thought to be necessary for lichen growth in the Negev. The findings may assist in evaluating weathering rates and paleoclimate reconstruction.
Is Obsidian Hydration Dating Affected by Relative Humidity?
Authors: Friedman Irving , Trembour Fred W. , Smith George I. , Smith Franklin L. 
Published: October 2002

AbstractExperiments carried out under temperatures and relative humidities that approximate ambient conditions show that the rate of hydration of obsidian is a function of the relative humidity, as well as of previously established variables of temperature and obsidian chemical composition. Measurements of the relative humidity of soil at 25 sites and at depths of between 0.01 and 2 m below ground show that in most soil environments, at depths below about 0.25 m, the relative humidity is constant at 100%. We have found that the thickness of the hydrated layer developed on obsidian outcrops exposed to the sun and to relative humidities of 30-90% is similar to that formed on other portions of the outcrop that were shielded from the sun and exposed to a relative humidity of approximately 100%. Surface samples of obsidian exposed to solar heating should hydrate more rapidly than samples buried in the ground. However, the effect of the lower mean relative humidity experiences by surface samples tends to compensate for the elevated temperature, which may explain why obsidian hydration ages of surface samples usually approximate those derived from buried samples.
Late Quaternary History of Tundra Vegetation in Northwestern Alaska
Authors: Anderson Patricia M. , Bartlein Patrick J. , Brubaker Linda B. 
Published: October 2002

AbstractPollen analysis of a new core from Joe Lake indicates that the late Quaternary vegetation of northwestern Alaska was characterized by four tundra and two forest-tundra types. These vegetation types were differentiated by combining quantitative comparisons of fossil and modern pollen assemblages with traditional, qualitative approaches for inferring past vegetation, such as the use of indicator species. Although imprecisely dated, the core probably spans at least the past 40,000 yr. A graminoid-Salixtundra dominated during the later and early portions of the glacial record. The middle glacial interval and the transition from glacial to interglacial conditions are characterized by a graminoid-Betula-Salixtundra. APopulusforest-Betulashrub tundra existed during the middle potion of this transition, being replaced in the early Holocene by aBetula-Alnusshrub tundra. The modernPiceaforest-shrub tundra was established by the middle Holocene. These results suggest that the composition of modem tundra communities in northwestern Alaska developed relatively recently and that throughout much of the late Quaternary, tundra communities were unlike the predominant types found today in northern North America. Although descriptions of vegetation variations within the tundra will always be restricted by the innate taxonomic limitations of their herb-dominated pollen spectra, the application of multiple interpretive approaches improves the ability to reconstruct the historical development of this vegetation type.
Holocene Paleoenvironmental Change in the Kenyan Central Rift as Indicated by Micromammals from Enkapune Ya Muto Rockshelter
Authors: Marean Curtis W. , Mudida Nina , Reed Kaye E. 
Published: October 2002

AbstractAn assemblage of micromammals, recovered from the Holocene levels of a rockshelter at 2400 m in the montane forest of the Mau Escarpment, were examined with the goal of testing and contributing to prior reconstructions of paleoenvironments in the Central Rift Valley of Kenya. Species representation in the assemblage is consistent with a drying of the Rift Valley lakes in the middle Holocene and suggests a decrease in forest accompanied by expanding grasslands near the site. Changes in the abundance of grassland species suggests an increase in the frequency of fires, probably the result of pastoral burning. The body size of the root rat (Tachyoryctes splendens) decreases from the early Holocene to the middle Holocene, and this may indicate increasing aridity or increasing temperature. We compare measures of species diversity (number of taxa, species richness, and the Shannon diversity index) for both micromammals and macromammals since species diversity may change with paleoenvironmental change. The macromammals show no changes in species diversity that are assignable to paleoenvironmental change, while the micromammals show a trend toward decreasing diversity from the early to middle Holocene, and then show an increase in diversity during the peak of the middle Holocene dry phase, though sample size effects may be confounding the patterning.
Mid-Holocene Erosion of Soil Catenas on Moraines near the Type Pinedale Till, Wind River Range, Wyoming
Authors: Dahms Dennis E. 
Published: October 2002

AbstractBuried soils are described from the floors of four kettles on Pinedale piedmont moraines of the southwestern Wind River Range, Wyoming, near the type locality of the Pinedale Till. The buried soils indicate that a previously unreported episode of slope erosion has occurred along adjacent catenas on some of the moraines in this region. Radiocarbon ages of the buried soils indicate that slope erosion occurred during the middle Holocene from 8540 ± 190 to 4800 ± 60 14C yr B.P. The presence of buried soils in moraine kettles indicates that profiles on the crests and backslopes of some of the moraines in this region are not the products of continuous post-Pinedale soil formation. Rather, the crest and backslope soils on Pinedale moraines result from two periods of soil development separated by an interval of erosion. Thus, soils on crests and backslopes are considered to be welded profiles. Relative-age studies that use soil data to estimate the age of moraines in this region must take into account the possibility that a mid-Holocene erosion episode affected the genesis and morphology of soils on the moraines. This study corroborates results of previous work that suggests that data from complete catenas are more useful for estimating the characteristic soil development on Quaternary moraines than are data derived from crests alone.
The Response of Northern Hemisphere Extratropical Climate and Vegetation to Orbitally Induced Changes in Insolation during the Last Interglaciation
Authors: Harrison Sandy P. , Kutzbach John E. , Prentice I. Colin , Behling Pat J. , Sykes Martin T. 
Published: October 2002

AbstractThe last interglaciation (substage 5e) provides an opportunity to examine the effects of extreme orbital changes on regional climates. We have made two atmospheric general circulation model experiments: P+T+ approximated the northern hemisphere seasonality maximum near the beginning of 5e; P-T- approximated the minimum near the end of 5e. Simulated regional climate changes have been translated into biome changes using a physiologically based model of global vegetation types. Major climatic and vegetational changes were simulated for the northern hemisphere extratropics, due to radiational effects that were both amplified and modified by atmospheric circulation changes and sea-ice feedback. P+T+ showed mid-continental summers up to 8°C warmer than present. Mid-latitude winters were 2-4°C cooler than present but in the Arctic, summer warmth reduced sea-ice extent and thickness, producing winters 2-8°C warmer than present. The tundra and taiga biomes were displaced poleward, while warm-summer steppes expanded in the mid latitudes due to drought. P-T- showed summers up to 5°C cooler than present, especially in mid latitudes. Sea ice and snowpack were thicker and lasted longer; polar desert, tundra, and taiga biomes were displaced equatorward, while cool-summer steppes and semideserts expanded due to the cooling. A slight winter warming in mid latitudes, however, caused warm-temperate evergreen forests and scrub to expand poleward. Such qualitative contrasts in the direction of climate and vegetation change during 5e should be identifiable in the paleorecord.
Ice-Volume Forcing of East Asian Winter Monsoon Variations in the Past 800,000 Years
Authors: Ding Zhongli , Liu Tungsheng , Rutter Nat W. , Yu Zhiwei , Guo Zhengtang , Zhu Rixiang 
Published: October 2002

AbstractParticle-size measurements of some typical loess-soil samples taken in different localities of the Chinese Loess Plateau demonstrate that the grain size ratio of <2 μm/>10 μm (%) can be used as an indicator of variations in intensity of the East Asian winter monsoon winds. Grain-size curves of the Baoji and Weinan sections show that this proxy indicator is very sensitive to loess-soil alterations. Analytical results also suggest that during soil-forming periods, eolian dust accumulation was still substantial and, hence, loess deposition can be regarded as a nearly continuous process during the Quaternary period. In this study we compared the Baoji grain-size time series with the SPECMAP marine isotope record with the objective of elucidating the dynamic linkage between changes in global ice volume and the winter monsoon circulation. Both records show good agreement at both time and frequency domains. In particular, the winter monsoon variations are also dominated by a 100,000 yr period over the past 800,000 yr. It is thus inferred that direct local insolation forcing could be less important in driving the East Asian winter monsoon variability, and, alternatively, variations in glacial-age boundary conditions may have played a key role in modulating and pacing its strength and timing.
Holocene Climate Effects on the Development of a Peatland on the Tuktoyaktuk Peninsula, Northwest Territories
Authors: Vardy Sheila R. , Warner Barry G. , Aravena Ramon 
Published: October 2002

AbstractSix cores were collected from a small peatland on the Tuktoyaktuk Peninsula, yielding up to 1.8 m of organic material and 1.2 m of ice-rich material. Stratigraphic relationships, radiocarbon dating, and pollen, plant macrofossil, and isotopic analyses are used to reconstruct the developmental history of the peatland. Organic matter began to accumulate in the basin about 7200 yr B.P., during a period when the climate is thought to have been warmer than present. Initially the permafrost table was probably below the bottom of the basin, and an open-water mineral wetland with emergent and submergent aquatic vegetation occupied the site. Enriched δ18O values from ice samples confirm the existence of an open water body with a water balance strongly affected by evaporation. Transformation to a graminoid fen peatland was underway by 6300 yr B.P. Permafrost and ice began to form in the peatland at this time. Low-centered polygons probably began to develop by 4700 yr B.P. and subsequently evolved into the high-centered polygons which characterise the southwestern part of the peatland today. Peat accumulation in the polygons has been extremely slow for the last 4000 years. The eastern, wetter part of the basin has largely remained unchanged since its inception about 7000 yr B.P. Development of the peatland may be linked to permafrost formation that was controlled by regional climate changes during the Holocene.