bluuebunny/crossref_metadata_2025 huggingface dataset:
KINESIN‐LIKE PROTEINS ARE INVOLVED IN POSTMITOTIC NUCLEAR MIGRATION OF THE UNICELLULAR GREEN ALGA MICRASTERIAS DENTICULATA
Authors: Holzinger Andreas , Lütz‐Meindl Ursula
Published: August 2002

The unicellular green alga Micrasterias denticulata performs a two‐directional postmitotic nuclear migration during development, a passive migration into the growing semicell, and a microtubule mediated backward migration towards the cell centre. The present study provides first evidence for force generation by motor proteins of the kinesin family in this process. The new kinesin specific inhibitor adociasulfate‐2 causes abnormal nuclear displacement at 18μM. AMP‐PNP, a non hydrolyseable ATP analogue or the general ATPase inhibitors calyculin A and sodium orthovanadate also disturb nuclear migration.

In addition kinesin‐like proteins are detected by means of immunoblotting using antibodies against brain kinesin, plant derived antibodies to kinesin‐like proteins and a calmodulin binding kinesin‐like protein. Immunoelectron microscopy suggests a correlation of conventional kinesin‐like proteins, but not of the calmodulin binding kinesin‐like protein to the microtubule apparatus associated with the migrating nucleus.
β‐ENDORPHIN IN GRANULOCYTES
Authors: Csaba G. , Kovács P. , Pállinger Éva
Published: August 2002

The literature indicates that β‐endorphin can be found in the mononuclear cells of peripheral blood. In the present experiments the endorphin content of granulocytes was studied, compared to lymphocytes as reference cells. Granulocytes as well, as lymphocytes contain endorphin. The granulocytes' endorphin content is much higher. Both lymphocytes and granulocytes are also able to take up endorphin from the milieu.
OVEREXPRESSION OF CYCLIN D1 IS ASSOCIATED WITH THE DECONDENSATION OF CHROMATIN DURING DEN‐INDUCED SEQUENTIAL HEPATOCARCINOGENESIS
Authors: Sundarrajan Monisha , Gupta Sanjay , Rao K. V. K.
Published: August 2002

D‐type cyclins regulate distinct cellular processes such as mitotic cell cycle control, differentiation and transcription. Deregulation of cyclin D1, a component of G1 checkpoint control, can result in enhanced genomic instability, cell transformation, and malignant neoplasia. However, a precise understanding of the molecular and cellular events underlying the regulation of the cyclin D1 gene remains to be elucidated. In this study, we examined the regulation of the cyclin D1 gene during n‐nitrosodiethylamine (DEN)‐induced sequential liver carcinogenesis. Northern blot studies showed an increase in the level of cyclin D1 mRNA. Southern blot analysis of the DNA restriction fragment showed no alterations and/or amplification in the coding region of the cyclin D1 gene. Bulk chromatin from DEN‐treated rat liver is much more sensitive to nuclease digestion than that from normal liver. Increased expression of the cyclin D1 gene is correlated to the upregulation of its transcription, mediated through chromatin decondensation during sequential hepatocarcinogenesis. Thus, the functional inter‐relationship between chromatin organization and gene expression appears to be of critical importance for liver tumour development.
DNA STRAND‐BREAKS INDUCED BY THE TOPOISOMERASE I INHIBITOR CAMPTOTHECIN IN UNSTIMULATED HUMAN WHITE BLOOD CELLS
Authors: Daza P. , Torreblanca J. , García‐Herdugo G. , Moreno F. J.
Published: August 2002

Camptothecin (CPT) and actinomicyn‐induced strand‐breaks, repair and apoptosis in unstimulated human blood cells were studied using the DNA comet assay, and electrophoresis of low molecular weight DNA extracts. On the one hand, incubation of G0 leukocytes for 1h with CPT induced DNA strand‐breaks that were observed using the single cell gel electrophoresis technique. On the other hand, internucleosomal DNA fragments were not observed, suggesting that apoptosis had not occurred. DNA‐strand‐breaks caused by CPT were repaired 24h after treatment; the migration of DNA fragments was assessed by a reduction in the number of comets. These data strongly suggest that the unexpected clastogenic effect of this topoisomerase I inhibitor is not due to the collision of the cleavage complex with the replication fork, since replication does not occur in G0. In our opinion, this effect could be due instead to the topoisomerase I enzyme being able to bind DNA in the absence of replication, probably in a way that is not strictly related to the progression of the cell cycle. Thus, CPT does not provoke apoptosis in quiescent leukocytes.
REAPPRAISAL OF G1‐PHASE ARREST AND SYNCHRONIZATION BY LOVASTATIN
Authors: Cooper Stephen
Published: August 2002

It has been proposed that lovastatin arrests cells in the G1‐phase of the division cycle, and that release from lovastatin inhibition produces a synchronized culture. A new method of methocel time‐lapse‐videography has been used to analyse cell division patterns following lovastatin treatment. Release of L1210 cells from lovastatin inhibition failed to produce synchronized divisions. Moreover, contrary to earlier proposals, lovastatin did not arrest cells with a G1‐phase amount of DNA. Analysis of previous reports of ‘synchronization’ and growth‐arrest support these findings. It is concluded that lovastatin neither synchronizes cells, nor arrests cells in the G1‐phase of the division cycle.
Combined Marine Proxy and Pollen Analyses Reveal Rapid Iberian Vegetation Response to North Atlantic Millennial-Scale Climate Oscillations
Authors: Roucoux Katherine H. , Shackleton Nicholas J. , de Abreu Lucia , Schönfeld Joachim , Tzedakis Polychronis C.
Published: August 2002

A deep-sea sediment core from the western Portuguese margin has provided a continuous, high-resolution record of millennial-scale climatic oscillations during the interval 9000–65,000 yr B.P. Pollen analysis of the same sequence allows direct, in situ assessment of the phase relationship between the North Atlantic climate system and vegetation changes on the adjacent landmass. This demonstrates for the first time that variability in NW Iberian tree population size closely tracked millennial-scale climate variability.
Subdivision of Glacial Deposits in Southeastern Peru Based on Pedogenic Development and Radiometric Ages
Authors: Goodman Adam Y. , Rodbell Donald T. , Seltzer Geoffrey O. , Mark Bryan G.
Published: August 2002

The Cordillera Vilcanota and Quelccaya Ice Cap region of southern Peru (13°30′–14°00′S; 70°40′–71°25′W) contains a detailed record of late Quaternary glaciation in the tropical Andes. Quantification of soil development on 19 moraine crests and radiocarbon ages are used to reconstruct the glacial history. Secondary iron and clay increase linearly in Quelccaya soils and clay accumulates at a linear rate in Vilcanota soils, which may reflect the semicontinuous addition of eolian dust enriched in secondary iron to all soils. In contrast, logarithmic rates of iron buildup in soils in the Cordillera Vilcanota reflect chemical weathering; high concentrations of secondary iron in Vilcanota tills may mask the role of eolian input to these soils. Soil-age estimates from extrapolation of field and laboratory data suggest that the most extensive late Quaternary glaciation occurred >70,000 yr B.P. This provides one of the first semiquantitative age estimates for maximum ice extent in southern Peru and is supported by a minimum-limiting age of ∼41,520 14C yr B.P. A late glacial readvance culminated ∼16,650 cal yr B.P. in the Cordillera Vilcanota. Following rapid deglaciation of unknown extent, an advance of the Quelccaya Ice Cap occurred between ∼13,090 and 12,800 cal yr B.P., which coincides approximately with the onset of the Younger Dryas cooling in the North Atlantic region. Moraines deposited <394 cal yr B.P. in the Cordillera Vilcanota and <300 cal yr B.P. on the west side of the Quelccaya Ice Cap correlate with Little Ice Age moraines of other regions.
Evolution of Soils on Quaternary Reef Terraces of Barbados, West Indies
Authors: Muhs Daniel R.
Published: August 2002

Soils on uplifted Quaternary reef terraces of Barbados, ∼125,000 to ∼700,000 yr old, form a climo-chronosequence and show changes in physical, chemical, and mineralogical properties with terrace age. Parent materials are dust derived from the Sahara, volcanic ash from the Lesser Antilles island arc, and detrital carbonate from the underlying reef limestone. Although some terrace soils are probably eroded, soils or their remnants are redder and more clay-rich with increasing terrace age. Profile-average Al2O3 and Fe2O3 content increases with terrace age, which partially reflects the increasing clay content, but dithionite-extractable Fe also increases with terrace age. Profile-average K2O/TiO2, Na2O/TiO2, and P2O5/TiO2 values decrease with terrace age, reflecting the depletion of primary minerals. Average SiO2/Al2O3 values also decrease with terrace age and reflect not only loss of primary minerals but also evolution of secondary clay minerals. Although they are not present in any of the parent materials, the youngest terrace soils are dominated by smectite and interstratified kaolinite-smectite, which gradually alter to relatively pure kaolinite over ∼700,000 yr. Comparisons with other tropical islands, where precipitation is higher and rates of dust fall may be lower, show that Barbados soils are less weathered than soils of comparable age. It is concluded that many soil properties in tropical regions can be potentially useful relative-age indicators in Quaternary stratigraphic studies, even when soils are eroded or changes in soil morphology are not dramatic.
Mineralogic and Climatic Interpretations of the Luochuan Loess Section (China) Based on Diffuse Reflectance Spectrophotometry
Authors: Ji Junfeng , Balsam William , Chen Jun
Published: August 2002

We examined the top 135 m, that is, the entire Pleistocene, of the classic Luochuan section on the Chinese Loess Plateau with a diffuse reflectance spectrophotometer from the near ultraviolet, through the visible, and into the near infrared. From the reflectance data we calculated sample brightness which, with some caveats, is a reasonable proxy for magnetic susceptibility. Mineralogic changes were identified by factor analyzing the first derivative of the percent reflectance data and examining samples with high factor scores. Two factors which explain about 96% of the cumulative variance are distinguished by the relative proportion of hematite and goethite, the minerals that are responsible for the color changes in the loess sequence. Both hematite and goethite are present in both loess and paleosol but goethite dominates in loess whereas hematite dominates in paleosol. The goethite factor exhibits an inverse correlation with magnetic susceptibility; the hematite factor exhibits a weak positive correlation with susceptibility. Paleoclimatic interpretations are drawn from comparison of susceptibility to the concentration of spectrally identified hematite. Based on this comparison, paleosols in the early Pleistocene Wucheng Formation are characterized by conditions that are drier than today, a “dry summer monsoon”, whereas later Pleistocene paleosols are characterized by a “wet summer monsoon”.
Holocene Vegetation Dynamics of Anticosti Island, Québec, and Consequences of Remoteness on Ecological Succession
Authors: Lavoie Martin , Filion Louise
Published: August 2002

The postglacial vegetation history of Anticosti Island in the Gulf of St. Lawrence, Québec, was reconstructed from pollen analysis of three sites, providing the first paleoecological data for the island. The earliest plant communities (8550–777014C yr B.P.; 9500–8500 cal yr B.P.) were characterized by a high representation of green alder (Alnus crispa), indicating an open environment with sparse spruce (Picea). Between 7770 and 370014C yr B.P. (8500–4000 cal yr B.P.), the island was colonized by mixed deciduous and coniferous forests dominated by paper birch (Betula papyrifera) and spruce. A major increase in the abundance of balsam fir (Abies balsamea) occurred ca. 370014C yr B.P. (4000 cal yr B.P.), indicating development of the closed fir–spruce forests as they exist today. The island's remoteness from continental seed plant sources influenced plant colonization, afforestation, and ecological succession. The Gulf of St. Lawrence slowed plant migration, and tree species had to spread from the Gaspé Peninsula. Repeated drops in fir pollen percentages during the last 4,000 years may reflect the activity of defoliating insects.
Late Pleistocene Detrital Sediment Yield of the Jura Glacier, France
Authors: Buoncristiani Jean-François , Campy Michel
Published: August 2002

Measures of present-day glacial erosion vary widely with the technique employed. This paper quantifies the glacial material trapped in a proglacial lake during the Würm glacial period. The Combe d'Ain site was occupied by a meltwater lake where all the detrital material entering it from the Jura glacier accumulated. Sediment yield is computed from three factors: (1) the size of the sediment source area, (2) the length of time the system operated, and (3) the volume of sediment trapped. The sediment budget of the lake system suggests a detrital sediment yield of 4400±1700 metric tons per square kilometer and per calendar year. This represents a denudation rate of 1.6±0.6 mm per year, illustrating that mechanical erosion by the Jura glacier is more intensive than other processes of erosion.
Late Quaternary Climate and Hydrology of Tropical South America Inferred from an Isotopic and Chemical Model of Lake Titicaca, Bolivia and Peru
Authors: Cross Scott L. , Baker Paul A. , Seltzer Geoffrey O. , Fritz Sherilyn C. , Dunbar Robert B.
Published: August 2002

A simple mass balance model provides insight into the hydrologic, isotopic, and chemical responses of Lake Titicaca to past climatic changes. Latest Pleistocene climate of the Altiplano is assumed to have been 20% wetter and 5°C colder than today, based on previous modeling. Our simulation of lacustrine change since 15,000 cal yr B.P. is forced by these modeled climate changes. The latest Pleistocene Lake Titicaca was deep, fresh, and overflowing. The latest Pleistocene riverine discharge from the lake was about 8 times greater than the modern average, sufficient to allow the expansion of the great paleolake Tauca on the central Altiplano. The lake δ18O value averaged about −13‰ SMOW (the modern value is about −4.2‰). The early Holocene decrease in precipitation caused Lake Titicaca to fall below its outlet and contributed to a rapid desiccation of paleolake Tauca. Continued evaporation caused the 100-m drop in lake level, but only a slight (1–2‰) increase (relative to modern) in δ18O of early Holocene lake waters. This Holocene lowstand level of nearly 100 m was most likely produced by a precipitation decrease, relative to modern, of about 40%. The lake was saline as recently as 2000 cal yr B.P. The timing of these hydrologic changes is in general agreement with calculated changes of insolation forcing of the South American summer monsoon.
Evidence for Millennial-Scale Climate Change During Marine Isotope Stages 2 and 3 at Little Lake, Western Oregon, U.S.A.
Authors: Grigg Laurie D. , Whitlock Cathy , Dean Walter E.
Published: August 2002

Pollen and geochemical data from Little Lake, western Oregon, suggest several patterns of millennial-scale environmental change during marine isotope stage (MIS) 2 (14,100–27,600 cal yr B.P.) and the latter part of MIS 3 (27,600–42,500 cal yr B.P.). During MIS 3, a series of transitions between warm- and cold-adapted taxa indicate that temperatures oscillated by ca. 2°–4°C every 1000–3000 yr. Highs and lows in summer insolation during MIS 3 are generally associated with the warmest and coldest intervals. Warm periods at Little Lake correlate with warm sea-surface temperatures in the Santa Barbara Basin. Changes in the strength of the subtropical high and the jet stream may account for synchronous changes at the two sites. During MIS 2, shifts between mesic and xeric subalpine forests suggest changes in precipitation every 1000–3000 yr. Increases in Tsuga heterophylla pollen at 25,000 and 22,000 cal yr B.P. imply brief warmings. Minimum summer insolation and maximum global ice-volumes during MIS 2 correspond to cold and dry conditions. Fluctuations in precipitation at Little Lake do not correlate with changes in the Santa Barbara Basin and may be explained by variations in the strength of the glacial anticyclone and the position of the jet stream.
Late Quaternary Vegetation and Climatic History of the Long Valley Area, West-Central Idaho, U.S.A.
Authors: Doerner James P. , Carrara Paul E.
Published: August 2002

Paleoenvironmental data, including pollen and sediment analyses, radiocarbon ages, and tephra identifications of a core recovered from a fen, provide a ca. 16,500 14C yr B.P. record of late Quaternary vegetation and climate change in the Long Valley area of west-central Idaho. The fen was deglaciated prior to ca. 16,500 14C yr B.P., after which the pollen rain was dominated by Artemisia, suggesting that a cold, dry climate prevailed until ca. 12,200 14C yr B.P. From ca. 12,200 to 9750 14C yr B.P. temperatures gradually increased and a cool, moist climate similar to the present prevailed. During this period a closed spruce–pine forest surrounded the fen. This cool, moist climate was briefly interrupted by a dry and/or cold interval between ca. 10,800 and 10,400 14C yr B.P. that may be related to the Younger Dryas climatic oscillation. From ca. 9750 to 3200 14C yr B.P. the regional climate was significantly warmer and drier than at present and an open pine forest dominated the area around the fen. Maximum aridity occurred after the deposition of the Mazama tephra (ca. 6730 14C yr B.P.). After 3200 14C yr B.P. regional cooling brought cool, moist conditions to the area; the establishment of the modern montane forest around the fen and present-day cool and moist climate began at ca. 2000 14C yr B.P.
The First Dated Eemian Lacustrine Deposit in Romania
Authors: Petroniu Onac Bogdan , Björkman Leif , Björck Svante , Clichici Octavian , Tamas Tudor , Peate David , Wohlfarth Barbara
Published: August 2002

A complex interglacial sequence of lacustrine sediments has been found near the village of Turbuta in NW Romania. Mollusk, plant macrofossil, and pollen analyses reflect climatic and environmental changes around the last interglacial climatic optimum. U-Th TIMS dating of snails strongly indicates an Eemian age of the organic sediments.
Late Holocene Changes in Precipitation and Hydrography Recorded in Marine Sediments from the Northeastern Caribbean Sea
Authors: Nyberg Johan , Kuijpers Antoon , Malmgren Björn A. , Kunzendorf Helmar
Published: August 2002

We present a record of climate variability spanning the last 2000 years obtained from sediment cores retrieved south and west of Puerto Rico in the northeastern Caribbean Sea. The records include lithological and mineral magnetic parameters as well as planktonic foraminifer data. For chronostratigraphic control, AMS14C and210Pb/137Cs measurements were made. Harmonic analysis of the values of the mineral magnetic parameters “saturation isothermal remanent magnetization” (SIRM), “anhysteric remanent magnetization divided by magnetic susceptibility” (ARM/χ), and “saturation isothermal remanent magnetization divided by magnetic susceptibility” (SIRM/χ) indicate the existence of a ∼200-year-long climate cycle in the northeastern Caribbean during the last 2000 years. The detected cycle may reflect changes in precipitation patterns over the low-latitude North Atlantic Ocean and surrounding continental areas. Higher organic carbon contents appear in the sediments both off southern and western Puerto Rico before and at the onset of the Little Ice Age around A.D. 1300 to 1500. This is indicative of increased run off and/or enhanced surface productivity possibly associated with more intense wind-induced upwelling. Major changes in the geochemical and mineral magnetic records around A.D. 850–1000 concur with changes in other records from the Caribbean and North African regions indicating a shift toward a more humid climate over the low-latitude North Atlantic.
Transport Direction of Peoria Loess in Nebraska and Implications for Loess Sources on the Central Great Plains
Authors: Mason Joseph A.
Published: August 2002

In the midwestern United States, large rivers draining the Laurentide Ice Sheet (LIS) were the most important sources of Peoria Loess, deposited during the last glaciation. Loess deposition near those rivers may have responded primarily to ice-sheet dynamics rather than direct effects of climatic change. In contrast, it has been proposed that thick Peoria Loess on the central Great Plains was derived mainly from unglaciated landscapes northwest of the main loess deposits. In this study, transport directions inferred from more than 600 measurements of Peoria Loess thickness in Nebraska are used to test the hypothesis that much of the Peoria Loess on the Great Plains is nonglaciogenic. A strong northwest to southeast thickness trend indicates that most Peoria Loess in Nebraska was transported from one or more unglaciated northwestern source areas rather than from glacially influenced river floodplains. The Missouri River (draining the LIS), the Platte River (draining alpine glaciers), and the Elkhorn River (unglaciated basin) were secondary sources. Their contribution is not detectable beyond a distance of 40–60 km. Peoria Loess deposition on the central Great Plains was largely a direct response to climatic change in the unglaciated source region.
The Classic Marine Isotope Substage 5e
Authors: Shackleton Nicholas J. , Chapman Mark , Sánchez-Goñi Maria Fernanda , Pailler Delphine , Lancelot Yves
Published: August 2002

Since its identification nearly fifty years ago, Marine Isotope Stage 5 (MIS 5) has been placed onto absolute time scales on the basis of three independent approaches. Cesare Emiliani, who set up the isotope stages (Emiliani, 1955), depended on uranium-series dating of the sediments, a method that today is regarded as not generally capable of yielding useful precision or accuracy. Broecker and van Donk (1970) pioneered the approach of correlating to radiometrically dated marine coral terraces; this has been much aided in recent years by improvements in the precision and accuracy of these age determinations that have flowed from the development of thermal ionization mass spectrometry (TIMS) for uranium-series dating (Edwards et al., 1986). The third approach is to use the astronomical record as a guide to the time scale. Martinson et al. (1987) generated a detailed time scale for MIS 5 using this approach. These authors suggested that the overall average error was of the order ±5000 yr, although the error would be smaller during interglacial periods with high precession-related variability, such as MIS5. At that time, the suggested confidence limits were smaller than typical values quoted for the radiometric dating of corals (typically ±6000 yr). Today the accuracy of the time scale of Martinson et al. (1987) is challenged by high-precision TIMS dates with quoted uncertainties of the order ±1000 yr or better. From the point of view of achieving a better understanding of the last interglacial period, the more serious disadvantage of the Martinson et al. (1987) time scale is the underlying hypothesis that all the proxy palaeoclimate records represent smoothly varying responses to changes in insolation; hence, there is no basis for estimating the duration of an extended interval with northern ice sheet volumes static at a size no greater than at present. From this point of view, the model of Gallée et al. (1993) is more promising, but that model is not at present sufficiently realistic to provide a reliable independent time scale. We have therefore chosen to depict the oxygen isotope record of core MD95-2042 (37°48′N, 10°10′W, water depth of 3146 m) on a time scale (Shackleton et al., 2001) that is based only on making use of selected radiometric dates obtained from fossil corals to calibrate the isotope record.
Last Interglacial Climates
Authors: Kukla George J. , Bender Michael L. , de Beaulieu Jacques-Louis , Bond Gerard , Broecker Wallace S. , Cleveringa Piet , Gavin Joyce E. , Herbert Timothy D. , Imbrie John , Jouzel Jean , Keigwin Lloyd D. , Knudsen Karen-Luise , McManus Jerry F. , Merkt Josef , Muhs Daniel R. , Müller Helmut , Poore Richard Z. , Porter Stephen C. , Seret Guy , Shackleton Nicholas J. , Turner Charles , Tzedakis Polychronis C. , Winograd Isaac J.
Published: August 2002

The last interglacial, commonly understood as an interval with climate as warm or warmer than today, is represented by marine isotope stage (MIS) 5e, which is a proxy record of low global ice volume and high sea level. It is arbitrarily dated to begin at approximately 130,000 yr B.P. and end at 116,000 yr B.P. with the onset of the early glacial unit MIS 5d. The age of the stage is determined by correlation to uranium–thorium dates of raised coral reefs. The most detailed proxy record of interglacial climate is found in the Vostok ice core where the temperature reached current levels 132,000 yr ago and continued rising for another two millennia. Approximately 127,000 yr ago the Eemian mixed forests were established in Europe. They developed through a characteristic succession of tree species, probably surviving well into the early glacial stage in southern parts of Europe. After ca. 115,000 yr ago, open vegetation replaced forests in northwestern Europe and the proportion of conifers increased significantly farther south. Air temperature at Vostok dropped sharply. Pulses of cold water affected the northern North Atlantic already in late MIS 5e, but the central North Atlantic remained warm throughout most of MIS 5d. Model results show that the sea surface in the eastern tropical Pacific warmed when the ice grew and sea level dropped. The essentially interglacial conditions in southwestern Europe remained unaffected by ice buildup until late MIS 5d when the forests disappeared abruptly and cold water invaded the central North Atlantic ca. 107,000 yr ago.
Last Interglacial and Early Glacial ENSO
Authors: Kukla George J. , Clement Amy C. , Cane Mark A. , Gavin Joyce E. , Zebiak Stephen E.
Published: August 2002

Although the link between insolation and climate is commonly thought to be in the high northern latitudes in summer, our results show that the start of the last glaciation in marine isotope stage (MIS) 5d was associated with a change of insolation during the transitional seasons in the low latitudes. A simplified coupled ocean-atmosphere model shows that changes in the seasonal cycle of insolation could have altered El Niño Southern Oscillation (ENSO) variability so that there were almost twice as many warm ENSO events in the early glacial than in the last interglacial. This indicates that ice buildup in the cooled high latitudes could have been accelerated by a warmed tropical Pacific.
Duration of Last Interglacial Conditions in Northwestern Greece
Authors: Tzedakis Polychronis C. , Frogley Michael R. , Heaton Timothy H.E.
Published: August 2002

A new astronomical calibration method for long pollen records from southern Europe is applied to the last interglacial interval of the Ioannina sequence, northwestern Greece. This shows that the last interglacial in this region, as defined by the presence of forest communities, lasted ca. 15,500 yr, from 127,300 to 111,800 yr B.P. Interglacial conditions developed within marine isotope substage (MIS) 5e and persisted into MIS 5d, lagging changes in global ice volume.
The Stability and the Abrupt Ending of the Last Interglaciation in Southeastern Siberia
Authors: Prokopenko Alexander A. , Karabanov Eugene B. , Williams Douglas F. , Khursevich Galina K.
Published: August 2002

Paleoproductivity records from Lake Baikal indicate that the last interglaciation in southeastern Siberia lasted ca. 12,000 yr from 127,000 to 115,000 yr B.P., was punctuated by a climatic oscillation about 120,000 yr ago, and ended abruptly with a rapid onset of regional glaciation during marine isotope substage (MIS) 5d. The Siberian equivalent of the MIS 5e–5d transition appears to lead the post-Eemian cold pulses in Europe and in the central North Atlantic by 5000 to 8000 yr. The Baikal record also registers a pronounced cold event during early MIS 5c, which correlates with the Montaigu event in pollen records from France. In Siberia, the climatic deterioration during the MIS 5d was a full-scale glacial pulse unlike the short, moderate cooling during the Montaigu event.
Evidence for the Timing and Duration of the Last Interglacial Period from High-Precision Uranium-Series Ages of Corals on Tectonically Stable Coastlines
Authors: Muhs Daniel R.
Published: August 2002

The last interglacial period has a timing and duration that can be estimated from U-series dating of emergent, coral-bearing deposits on tectonically stable coastlines. High-precision dating from Bermuda, the Bahamas, Hawaii, and Australia suggests that the last interglacial period had a sea level at least as high as present from ∼128,000 to 116,000 yr B.P. Sea level reached a near-present level more quickly after the close of the penultimate glacial period than at the close of the last glacial period and the duration of high sea level is longer than that implied by the deep-sea record.
Tentative Correlation of Pollen Records of the Last Interglacial at Grande Pile and Ribains with Marine Isotope Stages
Authors: Kukla George J. , de Beaulieu Jacques-Louis , Svobodova Helena , Andrieu-Ponel Valerie , Thouveny Nicolas , Stockhausen Hagen
Published: August 2002

Eemian lake deposits in Grande Pile and Ribains, France, correlate with marine isotope substages (MIS) 5e and 5d as delimited in two pollen-bearing deep-sea cores off Portugal. The Eemian forests in France lasted for approximately 20 millennia, from at least 126,000 to ca. 107,000 yr B.P. Oscillatory climate deteriorations began about 115,000 yr ago. An intense cold spell affected the region approximately 110,000 yr ago.
The Eemian Interglaciation in Northwestern Germany
Authors: Caspers Gerfried , Merkt Josef , Müller Helmut , Freund Holger
Published: August 2002

Hundreds of small lakes became filled with Eemian deposits following the retreat of Saalian ice in northwestern Germany. Weakly expressed climate oscillations have been inferred from some local pollen records of Late Saalian sediments. Sea level stood 7 m below the current northwest German sea-level datum (NN) during the interglacial climate optimum and decreased afterward. A uniform vegetational succession of the Eemian mixed forests, correlated with marine isotope stage (MIS) 5e, terminated with the demise of boreal woodlands marked by a steep increase in nonarboreal pollen. This is the onset of the early Weichselian Herning Stade, correlated with MIS 5d. No sharp climate oscillations during the Eemian have been documented. In the ending phase of the interglaciation, the climate deteriorated gradually. Dominant heath and grass tundras point to a substantial decline of summer temperature during the Herning Stade. Sea level then stood at −40 m NN. Sedimentological considerations, supported by counts of partly varved deposits, indicate that the Eemian lasted about 10,000–11,000 yr and the Herning for several millennia.
Burial of Different Types of Organic Carbon in Core 17962 from South China Sea since the Last Glacial Period
Authors: Jia Guodong , Peng Ping'an , Fang Dianyong
Published: August 2002

Total organic carbon (TOC), black carbon (BC), and land-derived organic carbon (LOC) extracted from marine sediment core 17962 from the southern South China Sea and analyzed by pyrolysis gas chromatography, elemental analyzers, and mass spectroscopy can be interpreted in terms of regional land biomass burning, climatic conditions, vegetation cover, and ocean paleoproductivity. Carbon from terrestrial sources, including BC and LOC, appears to be a significant component of TOC (3.1–39.3% range, 16.5% average for BC; 4.4–56.6% range, 14.6% average for LOC). The production of BC and LOC was only slightly higher during the Last Maximum Glaciation (LGM) than during the Holocene. Therefore, dramatic changes in climate and vegetation cover do not seem to have occurred at the Pleistocene–Holocene boundary. Paleoproductivity data calculated from marine organic carbon, proved to be more accurate than those calculated from TOC and exhibit the same pattern of temporal variation. However, the glacial–interglacial contrast in the refined palaeoproductivity is less evident than that calculated from TOC.
Late Quaternary Climate and Vegetation of the Sudanian Zone of Northeast Nigeria
Authors: Salzmann Ulrich , Hoelzmann Philipp , Morczinek Irena
Published: August 2002

The Lake Tilla crater lake in northeastern Nigeria (10°23′N, 12°08′E) provides a ca. 17,000 14C yr multiproxy record of the environmental history of a Sudanian savanna in West Africa. Evaluation of pollen, diatoms, and sedimentary geochemistry from cores suggests that dry climatic conditions prevailed throughout the late Pleistocene. Before the onset of the Holocene, the slow rise in lake levels was interrupted by a distinct dry event between ca. 10,900 and 10,500 14C yr B.P., which may coincide with the Younger Dryas episode. The onset of the Holocene is marked by an abrupt increase in lake levels and a subsequent spread of Guinean and Sudanian tree taxa into the open grass savanna that predominated throughout the Late Pleistocene. The dominance of the mountain olive Olea hochstetteri suggests cool climatic conditions prior to ca. 8600 14C yr B.P. The early to mid-Holocene humid period culminated between ca. 8500 and 7000 14C yr B.P. with the establishment of a dense Guinean savanna during high lake levels. Frequent fires were important in promoting the open character of the vegetation. The palynological and palaeolimnological data demonstrate that the humid period terminated after ca. 7000 14C yr B.P. in a gradual decline of the precipitation/evaporation ratio and was not interrupted by abrupt climatic events. The aridification trend intensified after ca. 3800 14C yr B.P. and continued until the present.
Lake Level and Climate Changes between 42,000 and 18,000 14C yr B.P. in the Tengger Desert, Northwestern China
Authors: Zhang Hucai , Wünnemann Bernd , Ma Yuzhen , Peng Jinlan , Pachur Hans-J. , Li Jijun , Qi Yuan , Chen Guangjie , Fang Hongbing , Feng Zhaodong
Published: August 2002

Multiple lines of stratigraphic, geochemical, and fossil data suggest that fresh-mesohaline paleolakes were widespread in the Tengger Desert of northwestern China and underwent major fluctuations during the late Pleistocene. The paleolakes started to develop at ca. 42,000 14C yr B.P. The lake levels were the highest between 35,000 and 22,000 14C yr B.P., during which Megalake Tengger dominated the landscape. The climatic conditions at this time were unique for this area and have no modern analogue. After an episode of decline between 22,000 and 20,000 14C yr B.P. and an episode of rebound between 20,000 and 18,600 14C yr B.P., the paleolakes started to desiccate and completely disappeared around 18,000 14C yr B.P. The environmental proxy data indicate that the Megalake Tengger formed under warm–humid climates. The reconstructed climatic variations appear to be correlative with the abrupt climatic events reconstructed for the North Atlantic.
Last Interglacial and Early Glacial Circulation in the Northern North Atlantic Ocean
Authors: Knudsen Karen-Luise , Seidenkrantz Marit-Solveig , Kristensen Peter
Published: August 2002

Studies of marine records from the northwestern European shelf and the northern North Atlantic suggest that last interglacial environments were less stable in this area than in the mid-latitude Atlantic. The influx of Atlantic water masses to the northern North Atlantic was generally higher, and the meridional temperature gradient was steeper, during the last interglaciation than during the Holocene. Strong north–south sea-surface-temperature gradients during the early Weichselian indicate a generally low influx of Atlantic water to the northern North Atlantic, even during interstades.
Mid- to Late-Wisconsin Pollen Record of San Felipe Basin, Baja California
Authors: Lozano-Garcı́a Marı́a Socorro , Ortega-Guerrero Beatriz , Sosa-Nájera Susana
Published: August 2002

A lacustrine sequence from Laguna Seca San Felipe, Baja California, in the southwestern Sonoran Desert, provides the first record of mid- to late-Wisconsin vegetation in one of the driest regions of North America. Pollen analysis was performed in the intermediate part of the sequence from ca. 44,000 to ca. 13,000 14C yr B.P. according to six 14C radiocarbon dates. Sedimentation of eolian sands prior to 44,000 14C yr B.P. indicates dry conditions. High pollen concentration of montane and chaparral species in the pollen assemblages contrast with the modern desert vegetation. Sixty-four pollen types were identified. The source of mid- to late-Wisconsin sedimentation must have been the plant communities in the surrounding highlands of the basin. Mid-Wisconsin pollen assemblages dominated by pines, junipers, and Artemisia reflect humid conditions in the area. By late Wisconsin time, a significant increment in junipers indicates a lowering in the altitudinal ranges of woodlands/chaparral. Pollen from wind-pollinated species is abundant while desert plants, specifically animal or insect pollinated species, are poorly represented. The San Felipe record does not identify the Last Glacial Maximum as the time of greatest effective moisture, as suggested by pluvial lake levels and other paleoclimatic evidence in the soutwestern United States.
Formal Status and Vegetational Development of the Eemian Interglacial in Northwestern and Southern Europe
Authors: Turner Charles
Published: August 2002

The terms Eem and Eemian have been applied to lithostratigraphic, chronostratigraphic, and biostratigraphic aspects of the last interglacial in western Europe. Eemian vegetational successions show strong uniformity at sites from western France across the North European Plain to Poland, suggesting, by comparison with the Holocene, that major pollen zones are broadly synchronous. South of the Alps and Pyrenees, a different vegetational succession is observed with no evidence for a substage of post-temperate cooling.
Problems of the Duration of the Eemian Interglacial in Europe North of the Alps
Authors: Turner Charles
Published: August 2002

Suggestions that the duration of the Eemian interglacial was about 11,000 yr, based on annually laminated sediment sequences in Germany, have been challenged in favor of a much longer interval. However, biostratigraphic evidence demonstrates why the Eemian sequences at Grande Pile and Ribains cannot be reliably used for alignment with the marine sequence, as applied by Kuklaet al.(2002, this issue) to estimate the duration of this interglacial. The long chronology they propose would imply not just coniferous but, for up to 5000 yr, fully temperate forest in central France coexisting with treeless heath and steppe tundra conditions in northwestern Europe, an unlikely climatic and ecological scenario. The proposal that the Eemian Interglacial in western Europe lasted for 17,000 or even 23,000 yr is rejected. A duration of no more than 13,000 yr is preferred, at least for sites north of the Alps and Pyrenees. The duration of temperate conditions in the Mediterranean region is less certain.
Thermohaline Circulation and Prolonged Interglacial Warmth in the North Atlantic
Authors: McManus Jerry F. , Oppo Delia W. , Keigwin Lloyd D. , Cullen James L. , Bond Gerard C.
Published: August 2002

Deep-sea sediment cores provide spatially coherent evidence for the climatic and hydrographic conditions in the subpolar North Atlantic during the last interglaciation. Taken together with similarly high-resolution terrestrial sequences, these records indicate a regional climatic progression, beginning with the extreme and variable climate late in the penultimate glaciation, continuing through a relatively stable climatic optimum during the interglaciation, and concluding with the reestablishment of the markedly variable regime that characterized the last 100,000-yr glaciation. Relatively mild conditions in much of the subpolar region significantly outlasted the minimum in global ice volume, despite declining summer insolation and the cooling influence of incipient proximal glaciers. These effects were partially offset by enhanced thermohaline circulation that paradoxically increased heat transport into the region while simultaneously providing the likely moisture source for the growth of large northern ice sheets. The inception of the last glacial cycle thus provides an example of the influence of ocean circulation on regional climate. In contrast to the apparent orbital pace of the ongoing ice-sheet growth, the subsequent deterioration of surface conditions was abrupt and dramatic.
Extracorporeal shock wave therapy for lateral epicondylitis—a double blind randomized controlled trial
Authors: Speed C. A. , Nichols D. , Richards C. , Humphreys H. , Wies J. T. , Burnet S. , Hazleman B. L.
Published: August 2002

Extracorporeal shock wave therapy (ESWT) is an increasingly popular therapeutic approach to the treatment of a number of soft tissue complaints. Whilst benefit has been demonstrated in calcific tendinitis, evidence is lacking for benefit in the management of non‐calcific rotator cuff disorders.

Aims: To perform a double‐blind placebo controlled trial of moderate dose ESWT in chronic lateral epicondylitis.

Methods: Adults with lateral epicondylitis were randomised to receive either active treatment (1500 pulses ESWT at 0.12 mJ/mm2) or sham therapy, monthly for three months. All were assessed before each treatment and one month after completion of therapy. Outcome measures consisted of visual analogue scores for pain in the day and at night.

Results: Seventy‐five subjects participated and there were no significant differences between the two groups at baseline. The mean duration of symptoms was 15.9 and 12 months in the ESWT and sham groups, respectively. Both groups showed significant improvements from two months. No significant difference existed between the groups with respect to the degrees of change in pain scores over the study period. In the ESWT group the mean (SD, range) pain score was 73.4 (14.5, 38–99) at baseline and 47.9 (31.4, 3–100) at three months. In the sham group the mean (SD, range) pain score was 67.2 (21.7, 12–100) at baseline and 51.5 (32.5, 3–100) at three months.

At three months, 50% improvement from baseline was noted in 35% of the ESWT group and 34% of the sham group with respect to pain.

Conclusions: There appears to be a significant placebo effect of moderate dose ESWT in subjects with lateral epicondylitis but there is no evidence of added benefit of treatment when compared to sham therapy.

© 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
Mathematical estimation of stress distribution in normal and dysplastic human hips
Authors: Mavčič B. , Pompe B. , Antolič V. , Daniel M. , Iglič A. , Kralj‐Iglič V.
Published: August 2002

By using a mathematical model of the adult human hip in the static one‐legged stance position of the body, the forces acting on the hip, peak stress in the hip joint and other relevant radiographic and biomechanical parameters were assessed. The aims were to examine if the peak stress in dysplastic hips is higher than in normal hips and to find out which biomechanical parameters contribute significantly to higher peak stress. The average normalized peak stress in dysplastic hips (7.1 kPa/N) was markedly higher (≈︁100%) than the average normalized peak stress in normal hips (3.5 kPa/N). The characteristic parameters that contributed to higher peak stress in dysplastic hips included the smaller lateral coverage of the femoral head, the larger interhip distance, the wider pelvis, and the medial position of the greater trochanter. These results are consistent with the hypothesis that stress distribution over weight‐bearing surface of the hip joint is the relevant parameter for assessment of the risk for developing coxarthrosis.

© 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
Expression and enzymatic activity of MMP‐2 during healing process of the acute supraspinatus tendon tear in rabbits
Authors: Choi Ho‐Rim , Kondo Seiji , Hirose Kazuyoshi , Ishiguro Naoki , Hasegawa Yukiharu , Iwata Hisashi
Published: August 2002

We investigated the spontaneous healing process of a surgically created supraspinatus tendon tear in rabbits with specific reference to the expression of matrix metalloproteinase‐2 (MMP‐2) and its time‐course change in enzymatic activity along with the expression of tissue inhibitors of metalloproteinases (TIMPs). A transverse, full thickness tear of the supraspinatus tendon was created and examined. Immunohistochemical analysis revealed that MMP‐2 positive cells were mainly localized at both cutting ends of the tendon, and reparative tissue encroached into the gap from the bursal side. The expression of TIMP‐1 was induced in the cells at not only the tendon edges but also the reparative tissue during the healing process. TIMP‐2 was constitutively expressed in both the tendon and the reparative tissue. Gelatin zymography using tissue culture media demonstrated latent and active forms of MMP‐2 and characteristic time‐linked changes of the enzymatic activity. Western blotting confirmed the bands as the latent form of MMP‐2. These results suggest that MMP‐2 is expressed and activated during the healing process of acute supraspinatus tendon tear and can play an important role in the remodeling process.

© 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
A model for intramembranous ossification during fracture healing
Authors: Thompson Zachary , Miclau Theodore , Hu Diane , Helms Jill A.
Published: August 2002

We have developed a method to study the molecular basis of intramembranous fracture healing. Unlike intramedullary rods that permit rotation of the fractured bone segments, our murine model relies on an external fixation device to provide stabilization. In this study we compare stabilized fracture callus tissues with callus tissues from non‐stabilized fractures during the inflammatory, soft callus, hard callus, and remodeling stages of healing. Histological analyses indicate that stabilized fractures heal with virtually no evidence of cartilage whereas non‐stabilized fractures produce abundant cartilage at the fracture site. Expression patterns of collagen type IIa (colIIa) and osteocalcin (oc) reveal that mesenchymal cells at the fracture site commit to either a chondrogenic or an osteogenic lineage during the earliest stages of healing. The mechanical environment influences this cell fate decision, since mesenchymal cells in a stabilized fracture express oc and fail to express colIIa. Future studies will use this murine model of intramembranous fracture healing to explore, at a molecular level, how the mechanical environment exerts its influence on healing of a fracture.

© 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.